A pilot died after his plane nosedived, according to neighbor Josh Nunnally, who witnessed the plane descending in the 10500 block of Robinson at Norwood Avenues in Riverside on Saturday March 16, 2019. (Photo by Cindy Yamanaka, The Press-Enterprise/SCNG)

RIVERSIDE — The pilot of a twin-engine plane that crashed March 16 behind a house two miles southwest of Riverside Municipal Airport was experiencing mechanical trouble even before he took off from a nearby airfield, according to the National Transportation Safety Board.

The agency’s preliminary report on the crash that killed 79-year-old Melvyn Caffey of Costa Mesa did not cite a specific cause, which will be identified in the final report that the NTSB is slated to issue in the next 12 months, but it indicated that Caffey was contending with “an electrical issue” minutes before he departed Chino Airport that Saturday morning.

The experienced aviator, who held an airline transport pilot license, was at the controls of his 1956 Beech D-50 Bonanza, intending to fly to Apple Valley, according to the NTSB report issued last week.

Investigators wrote that Caffey notified controllers at Chino that he was ready to go about 11:35 a.m., following a brief delay while sorting out the undisclosed electrical problem.

Once airborne and following a route that would take him over the Riverside (91) Freeway eastbound, the pilot advised SoCal Approach Control that he was “returning to the airport with electrical and engine issues,” the NTSB said.

“The pilot indicated that his right engine was out,” the report says.

Because he was losing altitude and closer to Riverside Municipal Airport, Caffey decided to divert there instead of returning to Chino less than 10 miles away, according to the NTSB.

The aviator lost control about 11:50 a.m. while maneuvering into the pattern at Riverside. According to witnesses, his dual-engine Bonanza went into a graveyard spiral, turning at least 1.5 revolutions to the right before crashing into the backyard of a single-story house at 10585 Robinson Ave., near Norwood Avenue.

A fence and patio were damaged, but the house was not, and no one on the ground was injured.